A prior proposal in an automotive application is shown in FIG. 1 for coupling and conditioning a signal from an inductive tachogenerator sensor 2 to a microcomputer unit (MCU) 4 which evaluates the sensor signal. A resistor network 6 coupled to a bias voltage supply V provides a bias point of V/2 for the tachogenerator. Network 6 together with capacitors 8 provide a low pass filter for filtering and attenuating the voltage output signal of the sensor 2, the voltage output signal varying between a few mV and several hundred volts. The sensor 2 is coupled via a twisted wire pair 10 to MCU 4, MCU 4 containing matched resistors 12, buffers 14 and a voltage comparator 16. Matched resistors 12 are provided for ensuring there is no voltage offset between the two inputs, but it is difficult to ensure matching of the resistors 12 both in terms of their relative values and their absolute values relative to resistor network 6. In addition there is the problem that the temperature of the tachogenerator 2 and nearby circuitry may be at a different temperature from MCU 4 which may create further inaccuracies.